Reduced engine deposits from dispersant treated with copper

ABSTRACT

The invention provides a lubricating composition containing an oil of lubricating viscosity and a dispersant treated with copper reagent. The invention further relates to methods of lubricating an internal combustion engine by supplying the described lubricating composition to the internal combustion engine. The invention further relates to the use of a dispersant treated with copper to reduce deposits on the inner surfaces of engine components.

FIELD OF INVENTION

The invention provides a lubricating composition containing a dispersanttreated with copper to reduce the formation of high temperatureinsoluble solids formed during exposure of the composition to heat. Theinvention further relates to the use of the lubricating composition inan internal combustion engine. The invention further relates to a methodof reducing insoluble deposits in an engine using said dispersanttreated with copper and said lubricating composition.

BACKGROUND OF THE INVENTION

It is known that lubricants become less effective during their use dueto exposure to the operating conditions of the device they are used in,including exposure to heat, oxygen, and partial combustion by-productsgenerated by the operation of the device. For example, engine oilbecomes less effective during its use, in part due to exposure of theoil to acidic and pro-oxidant by-products. These oxidized and acidichydrocarbons of the lubricant can then go on to cause corrosion, wearand deposit problems.

Modern engine designs tend to incorporate smaller sump volumes coupledwith higher operating temperatures than ever before. These designspecifications lead to greater oxidative stress on the lubricant andincreased propensity to form high temperature deposits on key enginezones such as the piston ring zone.

Given the continual demands placed on the lubricant by the modern enginedesigns mentioned above, modern engine testing is necessarily becomingmore severe. For instance, the industry standard high temperaturedeposit test (Sequence IIIG) is a very severe piston cleanliness testwith high sump temperatures and high load. There are a variety of benchtests that seek to simulate the deposit forming tendencies oflubricating oils in this and other engine tests including the Komatsuhot tube test (KHT). The procedure calls for circulating an oil througha hot glass tube (such as 232-320° C. and more typically 270-290° C.)for a specified period of time. At the end of test, the tube is ratedvisually for deposits with a rating of 10 being a perfectly clear tubeand 0 being a black tube. The test gauges the innate tendency of thelubricant to form deposits in the absence of combustion processes.

Current and proposed specifications for crankcase lubricants, such asGF-5 for passenger car motor oils, and PC-10 for heavy duty dieselengines specify increasingly stringent standards or limits to meetgovernment specifications. Of particular concern are sulfur andphosphorus limits. Sulfur and phosphorus from the lubricant can end upin the catalytic converter. It is widely believed that lowering theselimits in lubricants may have a serious impact on engine performance,engine wear, and oxidation of engine oils. This is because historicallya major contributor to phosphorus content in engine oils has been zincdialkyldithiophosphate (ZDP), and ZDP has long been used to impartantiwear and antioxidancy performance to engine oils. Thus, as reducedamounts of ZDP are anticipated in engine oils, there is a need foralternatives to impart protection against deterioration in one or moreof the properties of engine performance, engine wear, and oxidation ofengine oils. Such improved protection is desirable whether or not ZDPand related materials are included in the lubricant. Desirablelubricants may be low in one or more of phosphorus and sulfur

There is a need for dual function additives that provide engine depositcontrol at high operating temperatures along with one of theconventional functions of an engine oil additive (such as dispersing ofsoot). In addition, it is desirable if this dual function additive alsocan function with low levels of conventional antioxidants and/or lowlevels of metal or sulfur containing additives in the lubricant.

SUMMARY OF THE INVENTION

The present invention relates to copper modified dispersants. Thesecopper modified dispersant tend to minimize deposits formed as a resultof oil insoluble oxidation products on the walls of glass tubes andengine components. These copper modified dispersants also increase theoxidation induction times of the formulated lubricant in tests like theSAE CECL85.

It has now been discovered that the presence of copper, supplied forinstance in the form of a reaction product of aminic (also known asashless) dispersants and copper compounds, such as Cu⁺¹ or Cu⁺²,provides a beneficial effect on one or more of the above properties. Inparticular, such materials as copper PIB-succinimide dispersants imparta beneficial effect in one or more of the Komatsu Hot Tube depositsscreen test (KHT).

The desired metal can be supplied as a Cu-modified dispersant, such as asuccinimide dispersant, Mannich base, or hydrocarbyl based polymerdispersants. Such materials may be prepared by forming a copper mixedanhydride between a copper sulfate or copper acetate and ahydrocarbyl-substituted succinic anhydride, such as an alkenyl- oralkyl-succinic anhydride. The resulting copper-succinate intermediatemay be used directly or it may be reacted with any of a number ofmaterials, such as (a) a polyamine-based succinimide/amide dispersanthaving free, condensable —NH functionality; (b) the components of apolyamine-based succinimide/amide dispersant, i.e., an alkenyl- oralkyl-succinic anhydride and a polyamine, (c) a hydroxy-containingpolyester dispersant prepared by the reaction of a substituted succinicanhydride with a polyol, aminoalcohol, polyamine, or mixtures thereof.Alternatively, the copper-succinate intermediate may be reacted withother agents such as alcohols, aminoalcohols, ether alcohols, polyetheralcohols or polyols, or fatty acids, and the product thereof either useddirectly to impart copper to a lubricant, or else further reacted withthe succinic dispersants as described above. As an example of adispersant post-treated with metal, 1 part (by mole) of copper sulfate,copper acetate, and/or copper hydroxide may be reacted with 2 parts (bymole) of a polyisobutene-substituted succinic anhydride at 110-155° C.or in one embodiment 140-150° C., for 5 to 6 hours to provide a coppermodified dispersant or intermediate. The resulting material (30 g) maybe further reacted with a succinimide dispersant frompolyisobutene-substituted succinic anhydride and a polyethylenepolyaminemixture (127 g+diluent oil) at 155° C. for 1.5 hours, to produce acopper-modified succinimide dispersant.

Dispersants are well known in the field of lubricants and includeprimarily what is known as ashless-type dispersants and polymericdispersants. Ashless type dispersants are characterized by a polar groupattached to a relatively high molecular weight hydrocarbon chain.Typical ashless dispersants include nitrogen-containing dispersants suchas N-substituted long chain alkenyl succinimides, having a variety ofchemical structures including typically

where each R¹ is independently an alkyl group, frequently a polyisobutylgroup with a molecular weight of 500-5000, and R² are alkylene groups,commonly ethylene (C₂H₄) groups. Such molecules are commonly derivedfrom reaction of an alkenyl acylating agent with a polyamine, and a widevariety of linkages between the two moieties is possible in addition tothe representative imide structure shown above, including a variety ofamides and quaternary ammonium salts. Succinimide dispersants are morefully described in U.S. Pat. Nos. 4,234,435 and 3,172,892.

The invention further provides a method of lubricating an internalcombustion engine comprising the step of: supplying to the internalcombustion engine the lubricating composition described herein.

DETAILED DESCRIPTION OF THE INVENTION

Various preferred features and embodiments will be described below byway of non-limiting illustration.

The amounts of additives present in the lubricating compositiondisclosed herein are quoted on an oil free basis, i.e., amount ofactives, unless otherwise noted.

Oils of Lubricating Viscosity

The lubricating compositions of the invention comprise an oil oflubricating viscosity. Suitable oils include both natural and syntheticoils, oil derived from hydrocracking, hydrogenation, and hydrofinishing, unrefined, refined, re-refined oils or mixtures thereof.

Unrefined oils are those obtained directly from a natural or syntheticsource generally without (or with little) further purificationtreatment.

Refined oils are similar to the unrefined oils except they have beenfurther treated in one or more purification steps to improve one or moreproperties. Purification techniques are known in the art and includesolvent extraction, secondary distillation, acid or base extraction,filtration, percolation and the like.

Re-refined oils are also known as reclaimed or reprocessed oils, and areobtained by processes similar to those used to obtain refined oils andoften are additionally processed by techniques directed to removal ofspent additives and oil breakdown products.

Natural oils useful in making the inventive lubricants include animaloils, vegetable oils (e.g., castor oil,), mineral lubricating oils suchas liquid petroleum oils and solvent-treated or acid-treated minerallubricating oils of the paraffinic, naphthenic or mixedparaffinic-naphthenic types and oils derived from coal or shale ormixtures thereof.

Synthetic lubricating oils are useful and include hydrocarbon oils suchas polymerized, oligomerised, or interpolymerised olefins (e.g.,polybutylenes, polypropylenes, propyleneisobutylene copolymers);poly(1-hexenes), poly(1-octenes), trimers or oligomers of 1-decene,e.g., poly(1-decenes), such materials being often referred to as polya-olefins, and mixtures thereof; alkyl-benzenes (e.g., dodecylbenzenes,tetra-decylbenzenes, dinonylbenzenes, di-(2-ethylhexyl)-benzenes);polyphenyls (e.g., biphenyls, terphenyls, alkylated polyphenyls);diphenyl alkanes, alkylated diphenyl alkanes, alkylated diphenyl ethersand alkylated diphenyl sulphides and the derivatives, analogs andhomologs thereof or mixtures thereof.

Other synthetic lubricating oils include polyol esters (such asPriolube® 3970), diesters, liquid esters of phosphorus-containing acids(e.g., tricresyl phosphate, trioctyl phosphate, and the diethyl ester ofdecane phosphonic acid), or polymeric tetrahydrofurans. Synthetic oilsmay be produced by Fischer-Tropsch reactions and typically may behydroisomerised Fischer-Tropsch hydrocarbons or waxes. In oneembodiment, oils may be prepared by a Fischer-Tropsch gas-to-liquidsynthetic procedure as well as other gas-to-liquid oils.

Oils of lubricating viscosity may also be defined as specified in April2008 version of “Appendix E—API Base Oil Interchangeability Guidelinesfor Passenger Car Motor Oils and Diesel Engine Oils”, section 1.3Sub-heading 1.3. “Base Stock Categories”. In one embodiment, the oil oflubricating viscosity may be an API Group II or Group III oil. In oneembodiment, the oil of lubricating viscosity may be an API Group I oil.

The amount of the oil of lubricating viscosity present is typically thebalance remaining after subtracting from 100 wt. % the sum of the amountof the compound of the invention and the other performance additives.

The lubricating composition may be in the form of a concentrate and/or afully formulated lubricant. If the lubricating composition of theinvention (comprising the additives disclosed herein) is in the form ofa concentrate which may be combined with additional oil to form, inwhole or in part, a finished lubricant), the ratio of the of theseadditives to the oil of lubricating viscosity and/or to diluent oilinclude the ranges of 1:99 to 99:1 by weight, or 80:20 to 10:90 byweight.

The Dispersant Treated With Copper

The present invention provides a lubricating composition containing anoil of lubricating viscosity and an additive comprising a dispersanttreated with copper.

In one embodiments, the ashless dispersant reacted with copper,hereinafter additive, may be present in a lubricating composition in aconcentration from about 0.5 to about 10 weight percent, more desirablyfrom about 1 to about 5 weight percent, and preferably from about 1.5 toabout 3.5 weight percent based on the total weight of the lubricatingcompositions. Desirably, the amount of copper incorporated into thelubricant from treating the dispersant in the lubricating composition isfrom about 5, 6, or 7 to about 500 parts per million parts by weight(ppm) of lubricating composition, more desirably from about 5, 6, 8, or10 to about 50, 100, or 350 ppm, and in one embodiment, from about 40 or50 to 150 or 200 ppm.

Generally, the ashless dispersant and the copper compound will bereacted together at temperatures of at least 100° C., more desirably atleast 140° C. for times such as desirably at least 1 hour and moredesirably at least 2 or 4 hours so as to form a reaction product where asignificant portion of copper is physically or chemically associatedwith the dispersant. While a reaction product is the desired result, itis acknowledge that some copper and some ashless dispersant may remainin the form of reactants that haven't been converted to associatedmaterials.

Suitable dispersants for use in the compositions of the presentinvention include succinimide dispersants. In one embodiment, thedispersant may be present as a single dispersant. In one embodiment, thedispersant may be present as a mixture of two or three differentdispersants, wherein at least one may be a succinimide dispersant.

The succinimide dispersant may be a derivative of an aliphaticpolyamine, or mixtures thereof. The aliphatic polyamine may be aliphaticpolyamine such as an ethylenepolyamine, a propylenepolyamine, abutylenepolyamine, or mixtures thereof. In one embodiment, the aliphaticpolyamine may be ethylenepolyamine. In one embodiment, the aliphaticpolyamine may be selected from the group consisting of ethylenediamine,diethylenetriamine, triethylenetetramine, tetraethylenepentamine,pentaethylenehexamine, polyamine still bottoms, and mixtures thereof.

The dispersant may be a N-substituted long chain alkenyl succinimide.Examples of N-substituted long chain alkenyl succinimide includepolyisobutylene succinimide. Typically, the polyisobutylene from whichpolyisobutylene succinic anhydride is derived has a number averagemolecular weight of 350 to 5000, or 550 to 3000 or 750 to 2500.Succinimide dispersants and their preparation are disclosed, forinstance in U.S. Pat. Nos. 3,172,892; 3,219,666; 3,316,177; 3,340,281;3,351,552; 3,381,022; 3,433,744; 3,444,170; 3,467,668; 3,501,405;3,542,680; 3,576,743; 3,632,511; 4,234,435; Re 26,433; 6,165,235;7,238,650; and EP Patent Application 0 355 895 A.

Another class of ashless dispersant is Mannich base type. These arematerials which are formed by the condensation of a higher molecularweight, alkyl substituted phenol, an alkylene polyamine, and an aldehydesuch as formaldehyde. Such materials may have the general structure

(including a variety of isomers and the like) and are described in moredetail in U.S. Pat. No. 3,634,515.

Another class of ashless dispersant is high molecular weight ester type.These materials are similar to the above-described succinimides exceptthat they may be seen as having been prepared by reaction of ahydrocarbyl acylating agent and a polyhydric aliphatic alcohol such asglycerol, pentaerythritol, or sorbitol. Such materials are described inmore detail in U.S. Pat. Nos. 3,381,022 and 3,306,908.

Other dispersants include polymeric dispersant additives, which aregenerally hydrocarbon-based polymers which contain polar functionalityto impart dispersancy characteristics to the polymer.

Dispersants can also be post-treated by reaction with any of a varietyof agents. Among these are urea, thiourea, dimercaptothiadiazoles,carbon disulfide, aldehydes, ketones, carboxylic acids,hydrocarbon-substituted succinic anhydrides, nitriles, epoxides, boroncompounds, and phosphorus compounds. References detailing such treatmentare listed in U.S. Pat. Nos. 4,654,403 and 3,305,905.

Additional Performance Additives

The compositions of the invention may optionally comprise one or moreadditional performance additives. These additional performance additivesmay include one or more metal deactivators, viscosity modifiers,detergents, friction modifiers, antiwear agents, corrosion inhibitors,dispersants (other than the compound of the present invention),dispersant viscosity modifiers, extreme pressure agents, antioxidants,foam inhibitors, demulsifiers, pour point depressants, seal swellingagents, and any combination or mixture thereof. Typically,fully-formulated lubricating oil will contain one or more of theseperformance additives, and often a package of multiple performanceadditives.

In one embodiment, the invention provides a lubricating compositionfurther comprising an antiwear agent, a dispersant viscosity modifier, afriction modifier, a viscosity modifier, an antioxidant, an overbaseddetergent, or a combination thereof, where each of the additives listedmay be a mixture of two or more of that type of additive. In oneembodiment, the invention provides a lubricating composition furthercomprising an antiwear agent, a dispersant viscosity modifier, afriction modifier, a viscosity modifier (typically an olefin copolymersuch as an ethylene-propylene copolymer), an antioxidant (includingphenolic and/or aminic antioxidants), an overbased detergent (includingoverbased sulfonates and phenates), or a combination thereof, where eachof the additives listed may be a mixture of two or more of that type ofadditive.

In one embodiment, the lubricating composition of the invention furtherincludes an antiwear agent such as a phosphorus-containing antiwearagent such as a dithiophosphate agent such as a metal dihydrocarbyldithiophosphate (typically zinc dialkyldithiophosphate (ZDDP)), whereinthe metal dihydrocarbyl dithiophosphate contributes at least 100 ppm, atleast 200 ppm, or at least 250 ppm, or 200 ppm to 1000 ppm, or 250 or300 ppm to 800 ppm, or 300 or 400 ppm to 600 ppm of phosphorus to thelubricating composition. In one embodiment, the lubricating compositionis free of or substantially free (meaning less than 100, less than 50 orless than 20 ppm of phosphorus from a metal dialkyldithiophosphate suchas zinc dialkyldithiophosphate).

In one embodiment, the lubricating composition of the invention furthercomprises a dispersant viscosity modifier. The dispersant viscositymodifier may be present at 0 wt. % to 5 wt. %, or 0 wt. % to 4 wt. %, or0.05 wt. % to 2 wt. % of the lubricating composition.

Suitable dispersant viscosity modifiers include functionalizedpolyolefins, for example, ethylene-propylene copolymers that have beenfunctionalized with an acylating agent such as maleic anhydride and anamine; polymethacrylates functionalized with an amine, or esterifiedstyrene-maleic anhydride copolymers reacted with an amine. More detaileddescription of dispersant viscosity modifiers are disclosed inInternational Publication WO2006/015130 or U.S. Pat. Nos. 4,863,623;6,107,257; 6,107,258; and 6,117,825. In one embodiment, the dispersantviscosity modifier may include those described in U.S. Pat. No.4,863,623 (see column 2, line 15 to column 3, line 52) or inInternational Publication WO2006/015130 (see page 2, paragraph [0008]and preparative examples are described paragraphs [0065] to [0073]).

In one embodiment it is desirable if the lubricant composition has lowlevel or is free of metals selected from the group of molybdenum,titanium, and boron. In one embodiment the lubricant composition hasless than 100, less than 50, less than 20, less than 20 or 0 ppm ofmolybdenum based on the weight of the lubricant composition. Ppm is anabbreviation for parts by weight per million parts by weight of thetotal composition. In one embodiment the lubricant composition has lessthan 50, less than 30, less than 10, less than 5 or 0 ppm of titaniumbased on the weight of the lubricant composition. In one embodiment thelubricant composition has less than 100, less than 80, less than 50,less than 25, less than 10, or 0 ppm of boron based on the weight of thelubricant composition. In one embodiment the limitations on molybdenum,titanium, and boron are all together applied to the composition.

In one embodiment, the invention provides a lubricating compositionfurther comprising an overbased detergent. The overbased detergent maybe selected from the group consisting of sulfur-free phenates,sulfur-containing phenates, sulfonates, salixarates, salicylates, andmixtures thereof.

The overbased detergent may also include “hybrid” detergents formed withmixed surfactant systems including phenate and/or sulfonate components,e.g. phenate/salicylates, sulfonate/phenates, sulfonate/salicylates,sulfonates/phenates/salicylates, as described for example, in U.S. Pat.Nos. 6,429,178; 6,429,179; 6,153,565; and 6,281,179. Where, for example,a hybrid sulfonate/phenate detergent is employed, the hybrid detergentwould be considered equivalent to amounts of distinct phenate andsulfonate detergents introducing like amounts of phenate and sulfonatesoaps, respectively.

Typically, an overbased detergent may be sodium salts, calcium salts,magnesium salts, or mixtures thereof of the phenates, sulfur containingphenates, sulfonates, salixarates and salicylates. Overbased phenatesand salicylates typically have a total base number of 180 to 450 TBN.Overbased sulfonates typically have a total base number of 250 to 600,or 300 to 500. Overbased detergents are known in the art. In oneembodiment, the sulfonate detergent may be predominantly a linearalkylbenzene sulfonate detergent having a metal ratio of at least 8 asis described in paragraphs [0026] to [0037] of US Patent Publication2005065045 (and granted as U.S. Pat. No. 7,407,919). The linearalkylbenzene sulfonate detergent may be particularly useful forassisting in improving fuel economy. The linear alkyl group may beattached to the benzene ring anywhere along the linear chain of thealkyl group, but often in the 2-, 3- or 4-position of the linear chain.In some instances, the linear alkyl group may be attached inpredominantly the 2-position, resulting in the linear alkylbenzenesulfonate detergent. The overbased detergent may be present at 0 wt. %to 15 wt. %, 0.1 wt. % to 10 wt. %, 0.2 wt. % to 8 wt. %, or 0.2 wt. %to 3 wt. %. For example, in a heavy duty diesel engine the detergent maybe present at or 2 wt. % to 3 wt. % of the lubricating composition. Fora passenger car engine the detergent may be present at 0.2 wt. % to 1wt. % of the lubricating composition.

In one embodiment, the lubricating composition includes an antioxidant,or mixtures thereof. The antioxidant may be present at 0 wt. % to 15 wt.%, 0.1 wt. % to 10 wt. %, or 0.5 wt. % to 5 wt. % of the lubricatingcomposition.

Antioxidants include sulfurized olefins, alkylated diarylamines(typically alkylated phenyl naphthyl amines, for example thosecommercially available as Irganox® L 06 from CIBA, or alkylateddiphenylamines such as dinonyl diphenylamine, octyl diphenylamine,dioctyl diphenylamine), hindered phenols, molybdenum compounds (such asmolybdenum dithiocarbamates), or mixtures thereof.

The hindered phenol antioxidant often contains a secondary butyl and/ora tertiary butyl group as a sterically hindering group. The phenol groupmay be further substituted with a hydrocarbyl group (typically linear orbranched alkyl) and/or a bridging group linking to a second aromaticgroup. Examples of suitable hindered phenol antioxidants include2,6-di-tert-butylphenol, 4-methyl-2,6-di-tert-butylphenol,4-ethyl-2,6-di-tert-butylphenol, 4-propyl-2,6-di-tert-butylphenol or4-butyl-2,6-di-tert-butylphenol, or 4-dodecyl-2,6-di-tert-butylphenol.In one embodiment, the hindered phenol antioxidant may be an ester andmay include e.g., Irganox™ L-135 from Ciba. A more detailed descriptionof suitable ester-containing hindered phenol antioxidant chemistry isfound in U.S. Pat. No. 6,559,105.

Examples of friction modifiers include long chain fatty acid derivativesof amines, fatty esters, or epoxides; fatty imidazolines such ascondensation products of carboxylic acids and polyalkylene-polyamines;amine salts of alkylphosphoric acids; fatty alkyl tartrates; fatty alkyltartrimides; or fatty alkyl tartramides. In some embodiments, the termfatty, as used herein, can mean having a C8-22 linear alkyl group.

Friction modifiers may also encompass materials such as sulfurised fattycompounds and olefins, molybdenum dialkyldithiophosphates, molybdenumdithiocarbamates, sunflower oil or monoester of a polyol and analiphatic carboxylic acid.

In one embodiment, the friction modifier may be selected from the groupconsisting of long chain fatty acid derivatives of amines, long chainfatty esters, or long chain fatty epoxides; fatty imidazolines; aminesalts of alkylphosphoric acids; fatty alkyl tartrates; fatty alkyltartrimides; and fatty alkyl tartramides. The friction modifier may bepresent at 0 wt. % to 6 wt. %, or 0.05 wt. % to 4 wt. %, or 0.1 wt. % to2 wt. % of the lubricating composition.

In one embodiment, the friction modifier may be a long chain fatty acidester. In another embodiment, the long chain fatty acid ester may be amonoester or a diester or a mixture thereof, and in another embodiment,the long chain fatty acid ester may be a triglyceride.

Other performance additives such as corrosion inhibitors include thosedescribed in paragraphs 5 to 8 of U.S. application Ser. No. 05/038,319,published as WO2006/047486, octyl octanamide, condensation products ofdodecenyl succinic acid or anhydride and a fatty acid such as oleic acidwith a polyamine. In one embodiment, the corrosion inhibitors includethe Synalox® corrosion inhibitor. The Synalox® corrosion inhibitor maybe a homopolymer or copolymer of propylene oxide. The Synalox® corrosioninhibitor is described in more detail in a product brochure with FormNo. 118-01453-0702 AMS, published by The Dow Chemical Company. Theproduct brochure is entitled “SYNALOX Lubricants, High-PerformancePolyglycols for Demanding Applications.”

Metal deactivators including derivatives of benzotriazoles (typicallytolyltriazole), dimercaptothiadiazole derivatives, 1,2,4-triazoles,benzimidazoles, 2-alkyldithiobenzimidazoles, or2-alkyldithiobenzothiazoles; foam inhibitors including copolymers ofethyl acrylate and 2-ethylhexyl acrylate and copolymers of ethylacrylate and 2-ethylhexylacrylate and vinyl acetate; demulsifiersincluding trialkyl phosphates, polyethylene glycols, polyethyleneoxides, polypropylene oxides and (ethylene oxide-propylene oxide)polymers; pour point depressants including esters of maleicanhydride-styrene, polymethacrylates, polyacrylates or polyacrylamidesmay be useful.

Pour point depressants that may be useful in the compositions of theinvention include poly(alphaolefins), esters of maleicanhydride-styrene, poly(meth)acrylates, polyacrylates orpolyacrylamides.

In different embodiments, the lubricating composition may have acomposition as described in the following Table 1:

TABLE 1 Embodiments (wt. %) Additive A B C Additive of Invention, 0. 5to 10 1 to 6 1.5 to 3.5 dispersant treated with copper DispersantViscosity 0 or 0.05 to 5 0 or 0.05 to 4 0.05 to 2 Modifier OverbasedDetergent 0 or 0.05 to 15 0.1 to 10 0.2 to 8 Antioxidant aminic 0 or0.05 to 15 0.1 to 10 0.5 to 5 and/or phenolic Antiwear Agent, e.g. 0 or0.05 to 15 0.1 to 10 0.3 to 5 dithiophosphate Friction Modifier 0 or0.05 to 6 0.05 to 4 0.1 to 2 Viscosity Modifier 0 or 0.05 to 10 0.5 to 81 to 6 Any Other 0 or 0.05 to 10 0 or 0.05 to 8 0 or 0.05 to 6Performance Additive Oil of Lubricating Balance to 100 Balance to 100Balance to 100 Viscosity

The present invention provides a surprising ability to reduce hightemperature deposit formation on walls of the reactor in the KHT testsimply by modifying the dispersant with a few hundred ppm of copper.

INDUSTRIAL APPLICATION

In one embodiment, the invention provides a method of lubricating aninternal combustion engine comprising the step of supplying to theinternal combustion engine a lubricating composition as disclosedherein. Generally, the lubricant is added to the lubricating system ofthe internal combustion engine, which then delivers the lubricatingcomposition to the critical parts of the engine that require lubricationduring its operation.

The lubricating compositions described above may be utilized in aninternal combustion engine. The engine components may have a surface ofsteel or aluminum (typically a surface of steel), and may also be coatedfor example with a diamond like carbon (DLC) coating.

An aluminum surface may be comprised of an aluminum alloy that may be aeutectic or hyper-eutectic aluminum alloy (such as those derived fromaluminum silicates, aluminum oxides, or other ceramic materials). Thealuminum surface may be present on a cylinder bore, cylinder block, orpiston ring having an aluminum alloy, or aluminum composite.

The internal combustion engine may or may not have an Exhaust GasRecirculation (EGR) system. The internal combustion engine may be fittedwith an emission control system or a turbocharger. Examples of theemission control system include diesel particulate filters (DPF), orsystems employing selective catalytic reduction (SCR).

In one embodiment, the internal combustion engine may be a dieselfuelled or biofuelled engine (typically a heavy duty diesel engine), agasoline fuelled engine, a natural gas fuelled engine or a mixedgasoline/alcohol fuelled engine. In one embodiment, the internalcombustion engine may be a diesel fuelled engine and in anotherembodiment, a gasoline fuelled engine.

The internal combustion engine may be a 2-stroke or 4-stroke engine.Suitable internal combustion engines include marine diesel engines,aviation piston engines, low-load diesel engines, and automobile andtruck engines.

The internal combustion engine of the present invention is distinct fromgas turbine. In an internal combustion engine, individual combustionevents which through the rod and crankshaft translate from a linearreciprocating force into a rotational torque. In contrast, in a gasturbine (may also be referred to as a jet engine) it is a continuouscombustion process that generates a rotational torque continuouslywithout translation and can also develop thrust at the exhaust outlet.These differences result in the operation conditions of a gas turbineand internal combustion engine different operating environments andstresses.

The lubricant composition for an internal combustion engine may besuitable for any engine lubricant irrespective of the sulfur, phosphorusor sulfated ash (ASTM D-874) content. The sulfur content of the engineoil lubricant may be 1 wt. % or less, 0.8 wt. % or less, 0.5 wt. % orless, or 0.3 wt. % or less. In one embodiment, the sulfur content may bein the range of 0.001 wt. % to 0.5 wt. %, or 0.01 wt. % to 0.3 wt. %.The phosphorus content may be 0.2 wt. % or less, 0.12 wt. % or less, 0.1wt. % or less, 0.085 wt. % or less, 0.08 wt. % or less, 0.06 wt. % orless, 0.055 wt. % or less, or 0.05 wt. % or less. In one embodiment, thephosphorus content may be 100 ppm to 1000 ppm, or 200 ppm to 600 ppm.The total sulfated ash content may be 2 wt. % or less, 1.5 wt. % orless, or 1.1 wt. % or less, 1 wt. % or less, 0.8 wt. % or less, 0.5 wt.% or less, or 0.4 wt. % or less. In one embodiment, the sulfated ashcontent may be 0.05 wt. % to 0.9 wt. %, 0.1 wt. % to 0.2 wt. % or to0.45 wt. %. Desirably in one embodiment, the amount of sulfur from allthe sulfur containing additives is from about 500 or 1000 to about 2500ppm sulfur, based on the weight of the lubricant compositions, moredesirably from about 500 to about 1500 ppm.

In one embodiment, the lubricating composition may be an engine oil,wherein the lubricating composition may be characterized as having atleast one of (i) a sulfur content of 0.5 wt. % or less, (ii) aphosphorus content of 0.1 wt. % or less, (iii) a sulfated ash content of1.5 wt. % or less, or combinations thereof.

EXAMPLES

The invention will be further illustrated by the following examples,which set forth particularly advantageous embodiments. While theexamples are provided to illustrate the invention, they are not intendedto limit it.

Comparative Example 1 (CEX1) Synthesis of Succinimide Dispersant From2000 Mn Conventional Polyisobutylene

A 2 L 4-necked round bottom flask was equipped with a stirrer, droppingfunnel, sub-surface tube, thermowell, Dean-Stark trap and Friedrick'scondenser, charged with polyisobutylene succinic anhydride (550 g, 2000Mn, conventional PIBSA, TAN=68), diluent oil (505 g) and purged withnitrogen. Polyethylene amine still bottoms (25 g, 34 wt. % N) were addedto the dropping funnel. The mixture was warmed to 110° C. with stirring.The polyamine was added drop-wise to the sub-surface tube over 35 min.The temperature was increased to 155° C. and the preparation was stirredfor 5.25 h. 2.2 g water was collected in the Dean-Stark trap.Diatomaceous earth (16 g) was added to the mixture and the dispersantwas filtered through a supplemental pad of diatomaceous earth (16 g) toyield a succinimide dispersant as a clear brown oil (1013 g, KV100=548,% N=0.79).

Comparative Example 2 (CEX2) Synthesis of Al-Containing Dispersant

The dispersant of Comparative Example 1 (1400 g) was charged to a 2 L4-necked round bottom flask equipped with a stirrer, thermowell,sub-surface tube, Dean-Stark trap and Friedrick's condenser and theflask was purged with nitrogen. The dispersant was warmed to 90° C. withstirring. Al(PrO)₃ (45 g) was charged in one aliquot and the temperaturewas increased to 155° C. The mixture was stirred for 5 h, filteredthrough diatomaceous earth and cooled to yield a brown oil (1375 g,KV100=4626 cSt, 0.27% Al).

Comparative Example 3 (CEX3) Synthesis of La-Containing Dispersant

The procedure of Comparative Example 2 was used except the dispersant ofComparative Example 1 (1300 g) was treated with La(OH)₃ (7.1 g) to yielda brown oil (1178 g, KV100=487 cSt).

Comparative Example 4 (CEX4) Synthesis of Ba-Containing Dispersant

The procedure of Comparative Example 2 was used except the dispersant ofComparative Example 1 (1300 g) was treated with Ba(OH)₂.8H₂O (12 g) toyield a brown oil (1187 g, KV100=478 cSt, 0.38% Ba).

Comparative Example 5 (CEX5) Synthesis of Zn-Containing Dispersant

The procedure of Comparative Example 2 was used except the dispersant ofComparative Example 1 (1300 g) was treated with Zn(OAc)₂ (18 g) to yielda brown oil (1216 g, KV100=682 cSt, 0.39% Zn).

Example 6 (EX6) Synthesis of Cu-Containing Dispersant 1

The procedure of Comparative Example 2 was used except the dispersant ofComparative Example 1 (1300 g) was treated with CuSO₄ (13 g) to yield alight purple oil (1216 g, KV100=544 cSt, 0.08% Cu).

Example 7 (EX7) Synthesis of Cu-Containing Dispersant 2

The procedure of Comparative Example 2 was used except the dispersant ofComparative Example 1 (1300 g) was treated with Cu(OAc)₂.H₂O (17 g) toyield a green oil (1200 g, KV100=611 cSt, 0.39% Cu).

Example 8 (EX8) Dilution of Example 7 with Comparative Example 1 (50:50)

The Dipsersant 2 was mixed 50:50 by weight with Comparative Example 1 tosee the effect of concentration of the metal treated dispersant.

Example 9 (EX9) Dilution of Example 7 with Comparative Example 1 (25:75)

The Dipsersant 2 was mixed 50:50 by weight with Comparative Example 1 tosee the effect of concentration of the metal treated dispersant.

Preparative Example 10 (PEX10) Synthesis of High TBN SuccinimideDispersant from 2000 Mn Conventional Polyisobutylene

A 2 L 4-necked round bottom flask was equipped with a stirrer, droppingfunnel, sub-surface tube, thermowell, Dean-Stark trap and Friedrick'scondenser, charged with polyisobutylene succinic anhydride (600 g, 2000Mn, conventional PIBSA, TAN=73), diluent oil (635 g) and purged withnitrogen. Polyethylene amine still bottoms (43 g, 34 wt. % N) were addedto the dropping funnel. The mixture was warmed to 110° C. with stirring.The polyamine was added drop-wise to the sub-surface tube over 35 min.The temperature was increased to 155° C. and the preparation was stirredfor 5.25 h. 3.1 g water was collected in the Dean-Stark trap.Diatomaceous earth (18 g) was added to the mixture and the dispersantwas filtered through a supplemental pad of diatomaceous earth (18 g) toyield a succinimide dispersant as a clear brown oil (1117 g, KV100=183,% N=1.2).

Example 11 (EX11)

Synthesis of Cu-Containing Dispersant From Cu(OAc)₂xH₂O

The procedure of Comparative Example 2 was used except the dispersant ofComparative Example 10 (1300 g) was treated with Cu(OAc)₂xH₂O (16.6 g)to yield a brown oil (1200.0 g, KV100=611 cSt).

Lubricating Oils:

The materials from Examples CEX1- EX11 were blended into an API SNcapable lubricating oil (5W-30) in group II basestocks as detailed inTable 2. Component descriptions and treat rates are listed on a diluentoil free basis. Comparative Lubricant 1 contains Comparative DispersantExample 1 which is a baseline that contains no succinimide dispersantpost-treatment with a metal. Comparative Lubricants 2-5 (CL2-CL5)contain equivalent treat rates of Comparative Dispersant Examples 2-5containing Al, La, Ba and Zn post-treatments, respectively. These metalshave only one stable oxidation state. Lubricants 6-9 and 11 (L6-L9 andL11) have different types or amounts of copper as a post treatment forthe dispersant used in each example.

TABLE 2 Formulas Tested (Treat Rates on Oil Free Basis). Lubricant # CL1CL2 CL3 CL4 CL5 L6 L7 L8 L9 L11 Dispersant CEX1 CEX2 CEX3 CEX4 CEX5 EX6EX7 EX8 EX9 EX11 Disp. Treat 2.12 2.12 2.12 2.12 2.12 2.12 2.12 2.122.12 2.12 Group II Oil BALANCE to 100 g Ca Sulfonate¹ 0.74 g NaSulfonate² 0.17 AO³ 2.16 ZDP⁴ 0.79 VI Improver⁵ 0.7 Other⁶ 0.2 DispMetal — Al La Ba Zn Cu Cu Cu Cu Cu % M (ppm) 0 160 150 150 155 33 33 178 33 ¹Combination of 520 TBN and 690 TBN overbased calcium sulfonatedetergents ²Overbased sodium sulfonate detergent (650 TBN) ³C3/C6secondary zinc dialkyldithiophosphate (ZDDP) ⁴Combination of hinderedphenol, alkylated diphenyl amine, and sulfurized olefin⁵Ethylene-propylene copolymer ⁶Other additives include frictionmodifier(s), foam inhibitor(s), and/or pour point depressant(s)

Performance Testing:

The Lubricants from Table 1 were tested in the KHT test. Briefly, 5 mLof the test oil was pumped through a heated glass capillary tube at 0.31cc/h. The sample was purged with air at a rate of 10 cc/min. The samplewas circulated through the glass tube for 16 h while the tube is heatedto 280 ° C. At the end of test, the tube is visually rated according tothe scale found in FIG. 1 (10=clean tube, 0=dirty tube).

Table 3 shows the KHT performance of the Lubricants from Table 2. Thecomparative lubricants (CL1-CL5) all gave dirty black tubes (0) whilethe inventive lubricants (L6-L8) all gave much cleaner tubes in therange of 8.5-9.

TABLE 3 KHT Performance of the Lubricants from Table 1. Lubricant CL1CL2 CL3 CL4 CL5 L6 L7 L8 KHT Rating 0 0 0 0 0 8.5 9 8.5

It is known that some of the materials described above may interact inthe final formulation, so that the components of the final formulationmay be different from those that are initially added. The productsformed thereby, including the products formed upon employing lubricantcomposition of the present invention in its intended use, may not besusceptible of easy description. Nevertheless, all such modificationsand reaction products are included within the scope of the presentinvention; the present invention encompasses lubricant compositionprepared by admixing the components described above.

Each of the documents referred to above is incorporated herein byreference, as is the priority document and all related applications, ifany, which this application claims the benefit of. Except in theExamples, or where otherwise explicitly indicated, all numericalquantities in this description specifying amounts of materials, reactionconditions, molecular weights, number of carbon atoms, and the like, areto be understood as modified by the word “about.” Unless otherwiseindicated, each chemical or composition referred to herein should beinterpreted as being a commercial grade material which may contain theisomers, by-products, derivatives, and other such materials which arenormally understood to be present in the commercial grade. However, theamount of each chemical component is presented exclusive of any solventor diluent oil, which may be customarily present in the commercialmaterial, unless otherwise indicated. It is to be understood that theupper and lower amount, range, and ratio limits set forth herein may beindependently combined. Similarly, the ranges and amounts for eachelement of the invention may be used together with ranges or amounts forany of the other elements.

As used herein, the term “hydrocarbyl substituent” or “hydrocarbylgroup” is used in its ordinary sense, which is well-known to thoseskilled in the art. Specifically, it refers to a group having a carbonatom directly attached to the remainder of the molecule and havingpredominantly hydrocarbon character. Examples of hydrocarbyl groupsinclude:

-   (i) hydrocarbon substituents, that is, aliphatic (e.g., alkyl or    alkenyl), alicyclic (e.g., cycloalkyl, cycloalkenyl) substituents,    and aromatic-, aliphatic-, and alicyclic-substituted aromatic    substituents, as well as cyclic substituents wherein the ring is    completed through another portion of the molecule (e.g., two    substituents together form a ring);-   (ii) substituted hydrocarbon substituents, that is, substituents    containing non-hydrocarbon groups which, in the context of this    invention, do not alter the predominantly hydrocarbon nature of the    substituent (e.g., halo (especially chloro and fluoro), hydroxy,    alkoxy, mercapto, alkylmercapto, nitro, nitroso, and sulphoxy);-   (iii) hetero substituents, that is, substituents which, while having    a predominantly hydrocarbon character, in the context of this    invention, contain other than carbon in a ring or chain otherwise    composed of carbon atoms.

Heteroatoms include sulfur, oxygen, nitrogen, and encompass substituentsas pyridyl, furyl, thienyl and imidazolyl. In general, no more than two,preferably no more than one, non-hydrocarbon substituent will be presentfor every ten carbon atoms in the hydrocarbyl group; typically, therewill be no non-hydrocarbon substituents in the hydrocarbyl group.

While the invention has been explained in relation to its preferredembodiments, it is to be understood that various modifications thereofwill become apparent to those skilled in the art upon reading thespecification. Therefore, it is to be understood that the inventiondisclosed herein is intended to cover such modifications as fall withinthe scope of the appended claims.

What is claimed:
 1. An internal combustion engine lubricant compositioncomprising; a) an oil of lubricating viscosity, b) about 0.5 to 10 wt. %of a metal substituted dispersant based on the weight of said engine oillubricant composition, c) an antioxidant, d) an antiwear additive,wherein the metal of the metal dispersant comprises copper and theamount of metal substituted dispersant is such to provide about 5 to 500ppm of copper to said engine lubricant composition and wherein thelubricant composition comprises sulfur in an amount of less than 1 wt. %and phosphorus in an amount of less than 0.2 wt .% based on the weightof said lubricant composition.
 2. A composition according to claim 1,wherein said metal substituted dispersant is present from about 1 toabout 6 wt. % of said lubricant composition.
 3. A composition accordingto claim 1, wherein said copper is present from about 5 to about 100 ppmin said engine lubricant composition.
 4. A composition according toclaim 1, wherein said copper is present from about 40 to about 200 ppmin said engine lubricant composition.
 5. A composition according toclaim 1, wherein said metal substituted dispersant is present from about1.5 to about 3.5 wt. % in said engine lubricant composition.
 6. Acomposition according to claim 1, wherein said metal substituteddispersant is a metal substituted succinimide dispersant.
 7. Acomposition according to claim 1, further comprising an overbaseddetergent.
 8. A composition according to claim 1, wherein saidantioxidant comprises an aminic antioxidant and/or a phenolicantioxidant.
 9. A composition according to claim 8, wherein said aminicantioxidant is present in an amount from about 0.1 to about 10 wt. %based on said lubricant composition.
 10. A composition according toclaim 8, wherein said phenolic antioxidant is present in an amount fromabout 0.1 to about 10 wt. % based on said lubricant composition.
 11. Acomposition according to claim 1, wherein said anti-wear agent is ametal dithiophosphate antiwear agent.
 12. A composition according toclaim 1, wherein the lubricant composition comprises sulfur in an amountof less than 0.8 wt. % and phosphorus in an amount of less than 0.1 wt.% based on the weight of said lubricant composition.
 13. A compositionaccording to claim 1, wherein the lubricant composition comprisesmolybdenum in an amount of less than 100 parts per million parts inweight/weight (ppm), and boron in the amount of less than 100 ppm allbased on the weight of the lubricant composition.
 14. A method of usingan ashless dispersant reacted with a copper compound as an additive in alubricating composition to reduce engine deposits when said lubricant isexposed to use at temperatures of 150° C. or more wherein the amount ofsaid ashless dispersant reacted with said copper compound is present inan amount to provide about 5 to 500 ppm of copper to said lubricatingcomposition and wherein the lubricating composition comprises sulfur inan amount of less than 1 wt. % and phosphorus in an amount of less than0.2 wt. % based on the weight of said lubricating composition.
 15. Amethod of using an ashless dispersant according to claim 14, whereinsaid temperature is 200° C. or more.